Australia’s climate has entered into a new era of sustained extreme weather events, such as bushfires and dangerous heat waves, thanks to rising average temperatures, according to new reports by two of the country’s government climate science agencies.
Rising levels of carbon dioxide in the atmosphere, mostly from burning fossil fuels, have triggered even more dangerous bushfires, rising sea levels, and a rapid rise on days when temperatures reach extreme levels, the Bureau Meteorology and CSIRO said in Australia’s latest State of the Climate Report.
“What we are seeing now is beyond the reach of what was possible before,” said Dr Jaci Brown, director of the CSIRO Center for Climate Science.
While 2019 is the hottest record in Australia which helped fuel unprecedented wildfires, these temperatures will appear to be average once global warming hits 1.5C, the report said.
Among key findings, the report said Australia’s climate had warmed 1.44C since 1910 with the season of wildfires getting longer and more dangerous. Australia’s oceans have warmed to 1C and are acidifying.
In a briefing to reporters on Tuesday, Dr Karl Braganza, manager of the agency’s climate prediction service, said conditions in Australia were in line with projections over the past several decades.
But he said: “What we’re seeing now is a more pronounced shift to the extreme and we’re starting to feel how that shift in averages impacts extreme events.
“So we don’t feel the average temperature rise of 1.44C, but we did feel the heat wave and we felt the fire weather.”
Between 1960 and 2018, the report said there were 24 days when the country’s average maximum temperature reached 39C or higher. But 2019 alone has produced 33 such days.
Australia’s long-term greenhouse gas monitoring station at Cape Grim, in Tasmania’s northwestern tip, shows levels of CO2 accumulating in the atmosphere at an accelerating rate.
From 1980 to 1989, the amount of CO2 increased by 14 parts per million, but in the decade ending 2019 it increased by 23 parts per million.
Brown said that although the global economic slowdown due to the Covid-19 pandemic has led to reduced emissions, this is just a blip.
“Another way to think about this is if you’ve been eating junk food for 10 years and then you go on a diet for one day and jump on the scale the next morning and expect to see some change or decrease in dress sizes. It’s not that simple. It’s about long-term change, “he said.
“The big challenge for our children and grandchildren is how to flatten this curve.”
Emissions from fossil fuels – coal, oil and gas – are a major contributor to the growth of CO2 in the atmosphere, said the report, and were responsible for about 85% of emissions from 2009 to 2018.
Rising ocean temperatures, ocean heat waves and acidifying waters are also projected to continue, posing a significant threat to Australia’s coral reefs, Brown said.
Since 1970, rainfall in southwestern Australia has fallen by about 16% in the colder months between April and October, but much of northern Australia has seen an increase in rainfall.
The river flow meter also shows less water flowing through rivers in the southern part of the country since 1975.
“Australian agriculture is already facing significant challenges and disruptions from climate change, seen through record droughts, heat waves and rising temperatures,” Dr. Michael Battaglia, CSIRO director of agricultural and food research, said.
“The effects are widespread, affecting food production, supply chains, regional communities and consumer prices. Our farmers are resilient and capable, but climate change exposes them to significant risks. “
Australia’s temperature projections in the next two decades show each year to be warmer than “in a world without human influence”.
This, says the report, is known as the “emergence of climate change”.
While the current decade is warmer than any other decade over the past century, the report says it will likely be the coolest decade of the next century.
Australia will experience further warming, more very hot days and less cold days. The incidence of extreme heavy rain will also increase.
There may be fewer tropical cyclones in the future, the report said, but the cyclones that form will be more likely to become more intense.
Brown told the Australian Guardian that while the findings in the report were “contradictory”, it showed that “now is the time to act.”
The report’s release comes as the prime minister, Scott Morrison, faces pressure to keep up with major trading partners and tying Australia to net zero emissions targets by 2050.